Hi! I'm using a Mitel 5224 IP Phone at work, and it will call my personal cell phone, but there is no ringing, and I cannot hear the other person on the line, nor can they hear me.

You should have received a power supply with the phone. If it is new, and will not turn on at all, there is a good chance it is not plugged in correctly. You should have two Ethernet cables plugged into the rear of the phone. One for Data, and another for power.

Once on, it will still have to be set up by your IP Service provider.

Call history is programmed to save 0 calls need to program it to have more calls. Need to login to phone. System.

With phone idle press the up arrow key. This controls the contrast of the phone. Or try to reset the phone.If that doesn't work get a new phone.

the envelope button only works when it is flashing. Need to dial the voicemail or if there is a key programmed on the phone that rings voicemail.

you have to call reroute the phone to voicemail

only with a "Line Interface Module". This is a module that attaches to the back of the phone. Once attached a button will need to be programmed to allow it to work.

The phone will still need to connect to the telephone system - SX200ICP or 3300/MCD.

the stand requires configuration to tell it how to connect to your Wireless router. The default IP address is 192.168.1.20

The firmware should be upgraded to 2.0.3.ap51. This provides for better security and more options.

Your system admin or vendor will have to default the password.

No idea. Contact Plantronics for a headset. This phone will support a variety of headsets. www.plantronics.com.

This sounds like you have a call back message active on your phone, The callback is a through back to the days before we had Voice-mail, if you wanted a person to call you back you could activate their message light by pressing your message key while the called phone was ringing. To remove the light you would lift your handset and press the message key then select which party you wished to "callback", once the call was answered at the other end the light would be extinguished. Give this a try, I bet you will be surprised at the results.